Consider this example of an injection molding machine: Total machine cycle time is 16 seconds — 8 seconds to cycle the cylinder and 8 seconds of dwell time. An increase in productivity is desired, but dwell time cannot be changed due to machine loading and unloading requirements. The machine has a 15-gallon power unit working at 1,000 psi, but it is capable of 2,000 psi. Traditionally, the productivity increase would be achieved by increasing the size of the power unit to deliver a higher flow rate to the cylinder and speed up the cycle times. Instead, a 5-gallon accumulator was incorporated to supplement the flow rate of the pump and provide fluid to the cylinder. The pressure can be increased to 1,650 psi. This reduces the cylinder cycle time from 8 seconds to 4 seconds while maintaining the necessary 8 seconds of dwell time. At the original 16 seconds, 3.75 parts were produced per minute. With the accumulator addition, 5 parts per minute can be produced, a 33% increase in productivity.

The size of accumulator needed to reduce cycle time is determined by the maximum pressure the system can withstand, the minimum pressure required to do the work, and the cubic inches of fluid required to supplement pump flow. The necessary dwell time is determined by pump size. If 311 cubic inches are discharged from the accumulator during the machine cycle, the pump must be sized large enough to put the 311 cubic inches back into the accumulator during dwell time.

08-30-2014 10:21 上午

Top #4

Dave Evans

It's basically a reservoir of hydraulic power which is utilised when you need high flow and pressure to move a cylinder faster than the pump alone has the capacity to deliver. Think of a capacitor in electronics and it has a similar function. When the pump need not supply oil for movements or during cooling time the pump charges the accumulator which has a flexible bag inside it and is surrounded by nitrogen at a set pressure. When the pump is called upon to deliver more than it is capable of the pressure drops and the gas pressure forces the oil out of the flexible bag to help the pump and so through to the cylinder that requires the boost.
Hopefully that helps to explain it, a power reservoir.

Dave Evans

08-30-2014 12:47 下午

Top #5

Gregg Greider

It's like a hand grenade. No control, but you get a lot of speed and pressure. These were made before electric machines that can generate more pressure. Normally hydraulic machines can't get close to what an electric machine can generate.

08-30-2014 03:18 下午

Top #6

khaled nageeb

hydraulic accumulator is used to give us high speed and high pressure

08-30-2014 05:44 下午

Top #7

Reid Craig

used especially in filling large thin-walled items

08-30-2014 08:25 下午

Top #8

Jose Avellaneda

The accumulator is designed to boost the injection forward motion to aid in the filling process of thin walled parts. Not necessarily large parts but very thin walls. In most cases there are other options to achieve filling thin wall parts but than I would have to charge you for the consultation.